I bought an 8,000 pound 2 post asymmetrical lift when I built my shop and was racing my Porsche. It was one of the best decisions I ever made. Between my vehicles and those of the rest of my family it was getting used almost every week for years.
All I did when I poured my floor was to slop the compacted gravel to give me a 6” slab that was approximately 3’ x 3’ as I wasn’t sure of exactly the placement when I was pouring the floor. Never had any issues.

I did try (foolishly) to lift my 8300# F-350 diesel long bed but it was a no go so I would suggest at least a 10,000# set up.

Make sure you get the low profile arms if any of your cars are low. I still had to use a set of 2x12 pads to be able to lift my GT3.

Mine was a Bendpak and I had a couple of my guys help me over a Saturday install it.

Used to watch Brian quite a bit. I remember his lift video.

Looking at two post lifts, each arm appears to be rated at 1/4 the total lift capacity. For example, each arm of 10,000 pound lift is rated for 2,500 pounds. This would not work for my 8,000 pound truck if the lift points are behind the front axle as it weighs 4,700 pounds at the front axle.

Looking a a 12,000 pound lift, the pads are 5” tall which means I’s need to drive the Corvette and S2000 onto boards to get enough clearance over the pads.

It’s also looking like I don’t have the minimum thickness of concrete 4.25” for BendPak 2 post lifts <= 10,000 pounds or 6” for 12,000 pounds.

Looking at a four post lift, it seems I’d have the same clearance issues with bridge jacks as they have a minimum clearance height of 4”.

Our shop has had 12000# Mohawk 2 post lifts in service over 30 years. They needed 6" concrete pads but the rest of the floor could be 4". We service primarily Asian vehicles but also work on loaded plumbing and electrical vans, small dump trucks and tow trucks. A bonus for us is that the heavier lifts are wider which allows us more room to open doors. The lift arms fit pretty much everything that we deal with on a regular basis.